1. Field of the Invention
This invention relates to devices which regulate the flow of a cleaning liquid for wet air scrubbing devices. More particularly, this invention relates to adjustable cone control valves used with wet air scrubbing devices; the valves regulate the water introduced into a contaminant laden air stream.
2. Summary of the Prior Art
Gas scrubbing devices are used extensively to remove particulate contaminants from air. These devices have become increasingly important with the advent of air pollution requirements and worker safety standards. One particular application for these devices is in relation to paint spray booths.
In paint spray booths, the device to be painted is exposed to a paint spray stream. The over-spray is removed by drawing the contaminated atmosphere into contact with a fluid stream such as a water stream. The particulate contaminants are admixed with the fluid stream and separated from the gaseous atmosphere. The fluid stream can then be filtered and recycled.
One such system is described in U.S. Pat. No. 4,440,554 to Perry. In the gas scrubbing system of Perry, the water is fed to the scrubbing device by a series of metal cone-control valves located periodically along the sides of the gas scrubbing device. The water introduced through these cone-control valves is fed over a weir to a central drain. At the drain, the contaminant-laden air is admixed with the water, effectively separating the contaminants from the air.
Due to the nature of the wet scrubber system, the cone-control valves must operate in an atmosphere which is laden with particulate contaminants and solvent vapors associated with paint-spraying operations. This environment can cause corrosion, obstruction and eventual failure of the cone-control valves.
In air scrubbing devices of this type, it is necessary that each cone-control valve function to uniformly direct the flow of water. Uniform water dispersal is imperative to the efficient function of the scrubber. This requires exacting machining and tooling operations to obtain the necessary tolerances with conventional metal valve cones, this is difficult and costly.
Even well machined valve cones can be obstructed as they become coated with paint overspray and the like. Minute amounts of paint present on the valve cone can destroy the even flow characteristics of the valve. As the valve becomes fouled, it will require removal from the gas scrubbing device and time-consuming cleaning operations. This can result in expensive down-time for the entire device and any associated assembly line.
Another major drawback of conventional metal valves in wet air scrubbing applications of this sort is the inability of these devices to provide a fluid tight seal where the valve cone engages the water outlet. To stop fluid flow through a particular valve, seals or gaskets must be used. These seals are commonly O-rings located on or in the water outlet and, are generally composed of a compressible rubber or other suitable polymeric material. Prolonged use and exposure to solvent-laden atmospheres can cause distortion, swelling, and decomposition of the seal.
Thus, it would be desirable to manufacture a cone flow-directing valve for use in a gas scrubbing device which would be impervious to the solvent and contaminant-laden atmosphere into which it is placed. It is also desirable that the valve be easily cleanable should it become clogged. It is also desirable that the conical valve member be capable of sealingly seating with a compatible member to constrict or stop the fluid flow as desired. Finally, it is desirable that the valve be capable of being manufactured to close tolerances to provide maximum fluid flow directing capability.